Image Caption:Bradford has been pinpointed as an area where fraud is more likely

The commission said it was crucial the police and electoral officers in those areas improved safeguards against voter fraud ahead of May's local and European elections.

The commission report said: "The evidence and views we have heard raise significant questions about whether individuals within these communities are able effectively to exercise their right to vote, and whether they are able to participate in elections on the same basis as other electors across the UK.

"All electors should be free to cast their votes in the way they wish. It is not acceptable to explain or excuse electoral fraud on the basis of actual or perceived differences in cultural approaches to democratic participation."

"We have begun further work to identify relevant evidence in order to help address concerns about the vulnerability of some South Asian communities, specifically those with roots in parts of Pakistan or Bangladesh, to electoral fraud."

Image Caption:Voters should be forced to show ID before voting

The commission has also called for a change in the law by 2019 to make it mandatory for voters to show proof of identity at polling stations before voting.

However, it rejected calls to restrict postal voting and said such a move would prevent many innocent people from casting their vote.

But Electoral Commission chairwoman Jenny Watson said: "Proven cases of electoral fraud are rare and when it is committed, the perpetrators tend to be candidates or their supporters.

"Voters are the victims and sustained action is needed now to prevent fraud from taking place. Although the introduction of individual electoral registration this year will tighten up the registration system more can and should be done."

A Cabinet Office spokesman said: "The Government takes the issue of electoral fraud very seriously and we thank the Electoral Commission for their work on this issue. We will consider the recommendations in this report carefully and respond in due course."